The present invention relates generally to apparatus for emptying railroad cars carrying bulk material by rotating them about their longitudinal axis to dump the contents over the side of the cars into a hopper below and, thence, to a take-away system. More particularly, it relates to such a rotary car dumper which incorporates an efficient lump breaker apparatus to interrupt the flow of large lumps of dumped material and reduce the size of the lumps prior to entry to the hoppers and take-away system, whereby blockage of said system is prevented.
It is common practice to employ rotary car dumpers to empty long trainloads of bulk material, such as coal, various ores, and the like, wherein the trains may contain upwards of 100 to 150 loaded cars. In such operations, fast and dependable unloading of the rail cars, with little or no stoppage, is important in order to minimize the expense thereof. Bulk material being hauled by railway cars, however, commonly contains oversized lumps of product or the hauled material may freeze and form large lumps during transit in the winter months. Oftentimes when these cars are dumped on a rotary car dumper, the lumps are of such size that they easily plug-up the take-away system causing a subsequent shutdown of the unloading operation. The shutdown continues until the lumps are cleared. It is present practice in the art to install so-called "grizzly bars" with sized openings therein to prevent passage of large lumps into the take-away system. These grizzlies are usually positioned above the open hopper which lies beneath the rotary dumper. The large lumps retained on the grizzly are then broken up by portable and/or stationary equipment, such as dozers, track mounted hammermills, crushers, grinders, saws, manual picks and the like. Many things can prevent the commonly used breaker equipment from doing their intended job, e.g., the lumps may be buried in the flow of bulk material and, therefore, not accessible to the breaker, or the lumps may be too large to reach the breakers or may get hung up on some portion of the structure.
Presently known hammermill type breakers are track mounted on the stationary grizzly above the hopper pit area and travel beneath the rotary dumper in a direction parallel with the longitudinal axis thereof to break the lumps remaining on the grizzly after dumping. This prior arrangement requires approximately 4 feet of additional headroom to permit the hammermill to clear the bottom of the end rings of the dumper. This necessarily results in a more expensive dumper since the dumper pit must be deeper in order to accommodate the required, additional headroom and makes the retrofit of an existing dumper installation cost prohibitive.
The present invention solves many of the problems heretofore encountered in dumping bulk material containing oversized lumps or frozen portions therein, by providing a lump breaker apparatus which is mounted on the rotary dumper instead of in the hopper area. Since the breaker is supported directly on the dumper frame, the requirement for separate foundation supports for a breaker is eliminated. The present invention further provides a lump breaker in which the dumper operator has visual control over the positioning of the lumps and can selectively activate the lump breaker apparatus when required. Still further, the invention provides a lump breaker apparatus which is easily adaptable to be retrofitted to the end rings of a rotary car bumper presently in operation, without any modification or additions to the foundation structure thereof. The lump breaker device of the present invention requires no additional headroom beneath the dumper frame, thus, the dumper pit need not be deepened. Since the rotating lump breaker apparatus extends between the end rings of the dumper, minimum clearance between the end rings and the upper surface of the discharge hopper is possible. Likewise, no additional travel drive mechanism is required as is the case in the heretofore known hammermill-type traveling lump breakers of the prior art. Since the motorized lump breaker apparatus of the invention is mounted on the rotary dumper, it is less prone to damage due to its relatively safe location above the track level. The lump breaker of the present invention is easily controlled by the dumper operator and also very accessible for maintenance purposes.